1. Field of the Invention
The present invention relates generally to an apparatus and method for controlling a packet service in a mobile communication terminal, and in particular, to an apparatus and method for registering a packet network according to a resource status of the packet network in a mobile communication terminal.
2. Description of the Related Art
General Packet Radio Service (GPRS) was originally developed for a Global System for Mobile Communications (GSM), but was also adopted as an Interim Standard (IS)-136. GPRS is a bearer service for GSM, and it simplifies a wireless connection for a packet data network and improves its performance.
In using GPRS, a mobile terminal necessarily performs a GPRS attach procedure to register itself in a GPRS network. In the GPRS attach procedure, the mobile terminal notifies a Serving GPRS Support Node (SGSN) of a registered network position, IDentity (ID), security information, and various characteristics, which can be provided by the mobile terminal through an attach request message. Then, the SGSN accepts an attach attempt of the mobile terminal through an authentication process and makes the mobile terminal ready for the GPRS.
When the mobile terminal attempts the GPRS attach, the GPRS attach type is changed according to a network operation mode at a position where the mobile terminal is located. The GPRS attach type of the mobile terminal includes a “GPRS attach” type, a “GPRS attach while International Mobile Group Identity (IMSI) attach” type, and a “combined GPRS/IMSI attach” type.
Additionally, a GPRS attach mode regulates a time point when the mobile terminal should be attached to the GPRS network. Current network providers set up their preferable GPRS attach modes, and require the mobile terminal to perform a GPRS attach, based on the predetermined GPRS attach mode. Examples of the GPRS attach mode are an auto GPRS attach mode and a manual GPRS attach mode.
In the auto GPRS attach mode, the mobile terminal automatically performs the GPRS attach to maintain a GPRS attach state. The mobile terminal in the auto GPRS attach mode performs a GPRS attach and maintains a GPRS attach state when power is turned on or a new Public Land Mobile Network (PLMN) is selected. Unlike the auto GPRS attach mode, the mobile terminal performs a GPRS attach when a user demands the GPRS and switches to a non-GPRS attach state when the GPRS is terminated in the manual GPRS attach mode. The mobile terminal in the manual GPRS attach mode normally makes use of GSM service and performs a GPRS attach when the user demands the GPRS such as Wireless Application Protocol (WAP), Multimedia Message System (MMS), etc. When a corresponding service is terminated, the mobile terminal performs a GPRS detach.
When the mobile terminal attempts a GPRS attach, the network transmits a register reject message to the mobile terminal to restrict a GPRS network approach when the GPRS (or packet service (PS)) resource is insufficient. Upon failure of the GPRS attach, the mobile terminal periodically performs the GPRS attach until a GPRS connection is successful. In this case, signal load occurs and power consumption increases because the mobile terminal has to periodically perform the GPRS attach and a routing area update with the maximum number of times. Thereby decreasing the standby time. Moreover, in a network operation mode 1, the mobile terminal registers in terms of “combined attach” or “combined routing area update”. If failed, the mobile terminal has a limited service in the GSM network. Therefore, the mobile terminal needs to register its position in an additional GSM service (or Circuit Service (CS)).